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Discussion Starter · #1 ·
copy of posting before crash:

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I started to hijack someone else's similar post but thought it best to start my own. I looked through all the archives and couldn't find much to help.


I have owned this PB6100 for 5+ years and have only about 1100 hours on the bulb. I have received no warnings so far. One morning I got up and it was making a loud fan noise, but it was off. (in standby). The back fans weren't spinning at all and I can't get any display. I thought if I just unplugged it from the wall for a bit that might help, but it didn't.


Has anyone had any similar problems? Is there any way to do a reset without using the display? I think the 6200, 6110, etc are similar so if you own one of those and have any ideas please share. I don't want a $1150 paperweight, but it would probably not be worth it to send it to get it fixed.


Thanks in advance,


Mike

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Discussion Starter · #2 ·

Quote:
Originally Posted by SyncMaster750b /forum/post/14425344


copy of posting before crash:

**********************************************************

I started to hijack someone else's similar post but thought it best to start my own. I looked through all the archives and couldn't find much to help.


I have owned this PB6100 for 5+ years and have only about 1100 hours on the bulb. I have received no warnings so far. One morning I got up and it was making a loud fan noise, but it was off. (in standby). The back fans weren't spinning at all and I can't get any display. I thought if I just unplugged it from the wall for a bit that might help, but it didn't.


Has anyone had any similar problems? Is there any way to do a reset without using the display? I think the 6200, 6110, etc are similar so if you own one of those and have any ideas please share. I don't want a $1150 paperweight, but it would probably not be worth it to send it to get it fixed.


Thanks in advance,


Mike

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Reply from reconlabtech:


Sounds like either the lamp or the circuitry. In the early 2000's millions of bad capacitors flooded the market and made a lot of devices fail early. You could try a new lamp, they seem to still be available and under $300 but at this point, I'd say it's time to upgrade from 800x600 to HD. The Mitsubishi HC1500 is being closed out and can be found for @ $600 at BB if they have one left and there are a few machines in the $900 range like the Sharp DT-510. If you only need a 4:3 data PJ, there are several good ones for cheap these days.


BTW: Did you try pulling the lamp and then reinserting it and trying the power again?
 

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Discussion Starter · #3 ·
Thanks for the reply, reconlabtech!


That's not good to hear about the bad batch of capacitors though....that might be the cause unless someone else can think of something. I don't want to go and buy a new lamp in case that's not the problem....I wish I had one to test it with. There were no warnings about the lamp and it doesn't *look* damaged in any way. I like the idea of upgrading, but it's not really in the budget right now, especially since I spent $1200 5-6 years ago for the projector in the first place. In my head, I wanted it to last at least 10 years.


To answer your other question, I did try pulling the lamp, but it didn't change anything. Actually I took the cover off and tried to find a lose connection, or something obviously wrong, but nothing jumped out at me. How hard would it be to change the capacitor? I have a friend who is pretty handy with a soldering iron.


Anyone else have any ideas on what the problem could be?
 

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Discussion Starter · #4 ·
response from reconlabtech:


Get a strong light and look at the tops of every cap you can see and see if there is any leakage or bulging. Caps are easy to replace. I've repaired at least a dozen motherboards with a simple soldering iron.


Quote:
Originally Posted by SyncMaster750b /forum/post/14425355


Thanks for the reply, reconlabtech!


That's not good to hear about the bad batch of capacitors though....that might be the cause unless someone else can think of something. I don't want to go and buy a new lamp in case that's not the problem....I wish I had one to test it with. There were no warnings about the lamp and it doesn't *look* damaged in any way. I like the idea of upgrading, but it's not really in the budget right now, especially since I spent $1200 5-6 years ago for the projector in the first place. In my head, I wanted it to last at least 10 years.


To answer your other question, I did try pulling the lamp, but it didn't change anything. Actually I took the cover off and tried to find a lose connection, or something obviously wrong, but nothing jumped out at me. How hard would it be to change the capacitor? I have a friend who is pretty handy with a soldering iron.


Anyone else have any ideas on what the problem could be?
 

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Discussion Starter · #5 ·
I might just have to do that. Thanks for the suggestion. I'll have to wait a couple weeks though for my friend with the soldering/electronics expertise to get back into town. Any good sources for replacement capacitors?


How does the 6100/6200 behave when it needs a new bulb? Anyone remember? Do the two fans in the back still spin up when the bulb is dead?
 

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Discussion Starter · #6 ·
reply from reconlabtech:


Radio Shack, Parts Express, and ebay have been my sources.


I would give BenQ a call for technical support and ask them several questions to see if they will give you any troubleshooting ideas.


Quote:
Originally Posted by SyncMaster750b /forum/post/14425364


I might just have to do that. Thanks for the suggestion. I'll have to wait a couple weeks though for my friend with the soldering/electronics expertise to get back into town. Any good sources for replacement capacitors?


How does the 6100/6200 behave when it needs a new bulb? Anyone remember? Do the two fans in the back still spin up when the bulb is dead?
 

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Discussion Starter · #7 ·
Hey reconlabtech,


I started taking the projector apart, and on the one board there appears to be what I'm guessing you meant by leakage or bulging. Could this be enough to completely mess up the projector? I've attached a picture and you can see the one in the center looks pretty bad. It's also bulging, but it's hard to tell from that angle. What do you think?


Thanks in advance,

Mike
 

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Discussion Starter · #8 ·

Quote:
Originally Posted by SyncMaster750b /forum/post/14425379


Hey reconlabtech,


I started taking the projector apart, and on the one board there appears to be what I'm guessing you meant by leakage or bulging. Could this be enough to completely mess up the projector? I've attached a picture and you can see the one in the center looks pretty bad. It's also bulging, but it's hard to tell from that angle. What do you think?


Thanks in advance,

Mike
reply from reconlabtech:


DEFINITELY a blown cap. Good find! Get that replaced and you may be back in business.


Good photo too!
 

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Discussion Starter · #9 ·
wow, really....I wonder if that's all it was? Just a blown cap. I took some pictures of the bulb as well. It doesn't look blown, but then I don't know what to look for. It does seem to have something on the filament. What do you guys think?


P.S. Sorry for the confusing posts, I tried to recreate the lost thread so that it can help any one in the future or someone can add to it.


 

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Bulging caps like that would probably result in serious under-voltage on what looks like a power supply board. Good job, if you're not so sure about your soldering skills, find something to practice on. The pads for that should be quite large so it should be handily repairable with a typical soldering iron & solder sucker. Keep the heat on the pads to a minimum so they don't lift/break off but with moderate skill and taking care to not glob on any extra, you could get away quite lucky!


Cheers,

-M
 

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Discussion Starter · #11 ·

Quote:
Originally Posted by mvv /forum/post/14426028


Bulging caps like that would probably result in serious under-voltage on what looks like a power supply board. Good job, if you're not so sure about your soldering skills, find something to practice on. The pads for that should be quite large so it should be handily repairable with a typical soldering iron & solder sucker. Keep the heat on the pads to a minimum so they don't lift/break off but with moderate skill and taking care to not glob on any extra, you could get away quite lucky!


Cheers,

-M

I don't have any "soldering skills" so I'm going to practice removing and then soldering capacitors back on an old motherboard that I have laying around. Thanks for the advice, I hope this works!


Speaking of bad capacitors, the motherboard that I'm going to be using to practice on came from an old computer that I was having all sorts of problems with that I couldn't troubleshoot (and I'm a computer guy). Looking at it now, I see there must be 20 bulged and leaking capacitors on it. No wonder it wasn't working. I also had a TV die on me not too long ago, but it was covered un warranty. Could dirty power coming into my apartment be causing all of these problems with capacitors?
 

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Almost impossible to know without taking some readings but I think bad power would manifest itself in other ways. Do you go though a lot of light bulbs? Do you computers seem to crash more than they 'should' etc...

It could be that you've had a few more caps from the "bad batch" of caps mentioned by reconlabtech...


I have a motherboard like that too - next time I have a really flaky computer, I'll be inspecting the mobo first! I wasted hours on that one before I noticed the problem.


-M
 

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Discussion Starter · #13 ·
Update


I got all the soldering materials, and taught myself how to solder. I found a replacement capacitor and discharged all the old ones on the internal power boards. I practiced soldering and desoldering on an old motherboard for a couple hours. I removed the old capacitor and replaced it with the new one.


Spent about 2 hours putting everything back together and powered it up. The good news is that the capacitor WAS causing the problem of the fans and light not coming on. So the lamp and the back fans turned on and I was happy. The bad news is that the mainboard might have been fried in whatever incident that caused the capacitor to blow in the first place....or the blown capacitor killed the mainboard. All that I get is a white or grey screen. No menu or anything. :-(


Anyone have any experience with a white or grey screen?
 

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Good job with the soldering iron - Too bad you're not back in business yet. Assuming the optics are assembled properly it sounds like the next problem is with a video circuit... These get a lot harder to troubleshoot and may require some special equipment.


Anyone?
 

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Discussion Starter · #15 ·

Quote:
Originally Posted by mvv /forum/post/14435898


Good job with the soldering iron - Too bad you're not back in business yet. Assuming the optics are assembled properly it sounds like the next problem is with a video circuit... These get a lot harder to troubleshoot and may require some special equipment.


Anyone?

Thanks, I'm happy I didn't mess up the power/fan board with my lack of experience in soldering. In the end I took my time and practiced first and it all worked out. I'm going to take a look at the optics part of the set up again because it was 1:30 in the morning and I wasn't thinking 100% straight at the time. I already took the main board out again and reseated all the connectors with no luck. I'm hoping that I put something back on incorrectly, and by taking it apart again I can get it right this time.


I don't think I will try to repair the main board, just replace it if it's not too expensive. I guess the only place to get them is Benq, so I will give them a call.
 

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Discussion Starter · #16 ·
Well I took the optical unit apart again and looked for something obviously wrong, but couldn't find anything. Put everything back together and still get the same white image. Here's an attachment(s). Normally I wouldn't post a picture of a white image, but around the edges it looks a little odd to me. And something you can't see on the photo is that at the edge there is about 10% of the image where the projector looks like it's trying to do black, then another 20% of the image where the projector looks like it's try to do gray. It looks like a frame or something. Did I forget to put something back and and it fell behind the fridge or something?


Any ideas?

 

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When you replaced your cap, did you make sure to put the new one in with the same polarity as the old one? There is a positive and a negative lead...


Probably should have mentioned that earlier. Darn. I'd start loking over the other caps but it is possible that something else is also gone. If recapping is easy and cheap, then keep replacing them. It's probably a better idea anyway.
 

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Discussion Starter · #19 ·

Quote:
Originally Posted by reconlabtech /forum/post/14442653


When you replaced your cap, did you make sure to put the new one in with the same polarity as the old one? There is a positive and a negative lead...


Probably should have mentioned that earlier. Darn. I'd start loking over the other caps but it is possible that something else is also gone. If recapping is easy and cheap, then keep replacing them. It's probably a better idea anyway.

No worries, I made sure that I had the right polarity when I replaced the cap. I did a bit of reading before I jumped into anything. Replacing the cap got past the first problem of the bulb and back fans not coming on. Now I just have the problem of a white image. I need to figure out how to test the rest of the capacitors (without replacing), then replace if needed.


I wouldn't say removing the capacitor and putting a new one on was in any way easy for me. I think I got lucky my first time around. If I don't have to replace any more, then I'm reluctant to do so.


From what I can guess there's a ballast, a "fan power board", and small power board and the main board. I guess I'll have to test the capacitors on all of them.....once I figure out how to.
 

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Testing Capacitors with a Multimeter

Some DMMs have modes for capacitor testing. These work fairly well to determine approximate uF rating. However, for most applications, they do not test at anywhere near the normal working voltage or test for leakage. Normally, this type of testing requires disconnecting at least one lead of the suspect capacitor from the circuit to get a reasonably accurate reading - or any reading at all. However, newer models may also do a decent job of testing capacitors in-circuit. Of course, all power must be removed and the capacitors should be discharged. This will generally work as long as the components attached to the capacitor are either semiconductors (which won't conduct with the low test voltage) or passive components with a high enough impedance to not load the tester too much. The reading may not be as accurate in-circuit, but probably won't result in a false negative - calling a capacitor good that is bad. But I don't know which models are better in this regard.

CAUTION: For this and any other testing of large capacitors and/or capacitors in power supply, power amplifier, or similar circuits, make sure the capacitor is fully discharged or else your multimeter may be damaged or destroyed!


However, a VOM or DMM without capacitance ranges can make certain types of tests.


For small caps (like 0.01 uf or less), about all you can really test is for shorts or leakage. (However, on an analog multimeter on the high ohms scale you may see a momentary deflection when you touch the probes to the capacitor or reverse them. A DMM may not provide any indication at all.) Any capacitor that measures a few ohms or less is bad. Most should test infinite even on the highest resistance range.


For electrolytics in the uF range or above, you should be able to see the cap charge when you use a high ohms scale with the proper polarity - the resistance will increase until it goes to (nearly) infinity. If the capacitor is shorted, then it will never charge. If it is open, the resistance will be infinite immediately and won't change. If the polarity of the probes is reversed, it will not charge properly either - determine the polarity of your meter and mark it - they are not all the same. Red is usually **negative** with (analog) VOMs but **positive** with most DMMs, for example. Confirm with a marked diode - a low reading across a good diode (VOM on ohms or DMM on diode test) indicates that the positive lead is on the anode (triangle) and negative lead is on the cathode (bar).


If the resistance never goes very high, the capacitor is leaky.


The best way to really test a capacitor is to substitute a known good one. A VOM or DMM will not test the cap under normal operating conditions or at its full rated voltage. However, it is a quick way of finding major faults.


A simple way of determining the capacitance fairly accurately is to build an oscillator using a 555 timer. Substitute the cap in the circuit and then calculate the C value from the frequency. With a few resistor values, this will work over quite a wide range.


Alternatively, using a DC power supply and series resistor, capacitance can be calculated by measuring the rise time to 63% of the power supply voltage from T=RC or C=T/R.
 
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